抛物线y=4x2在点(1,4)处的切线方程是______.
y′=8x
当x=1得f′(1)=8
所以切线方程为y-4=8(x-1)
即8x-y-4=0
故答案为:8x-y-4=0
令牌总线网在物理上是总线网,而在逻辑上是______网。
— Do you have any plans for your winter vacation?
— I __________ Hainan next Sunday. [ ]
A. am leaving
B. am leaving for
C. leave for
D. leave